Thank you for your comment. Has the problem been resolved? There seems to be a rare problem with Itch's purchase link.
https://itch.io/t/622457/purchase-not-linked-to-any-account
https://itch.io/t/3129707/game-i-purchased-not-opening
https://itch.io/t/4453224/cant-access-games-purchased-in-bundle-due-to-malicious...
I don't know why the link can't be displayed to you, but I’m sorry for the trouble. If anyone else has encountered a problem like this, please feel free to leave a comment.